NASA's $125 million Mars Orbiter presumed destroyed

PASADENA, Calif. -- A $125 million NASA spacecraft that had traveled 416 million miles to Mars vanished Thursday as it was about to go into orbit around the Red Planet and was feared destroyed.

It was the second time in six years that a NASA spaceship was lost just as it reached Mars.

The Mars Climate Orbiter, which was on a mission to study the planet's weather and look for signs of water, apparently flew too close to the Martian atmosphere and broke apart or burned up, the space agency said.

Human or software error was probably to blame. NASA said mechanical problems were ruled out.

The apparent loss, after the $1 billion Mars Observer probe disappeared in 1993, comes as Congress is threatening to cut a large portion of NASA's space exploration budget and the agency is trying to show that it can design ''faster, cheaper and better'' missions.

NASA officials said failures are to be expected, since probes are now being launched every 26 months. They also pointed to their successes, such as the Mars Global Surveyor spacecraft and the Mars Pathfinder, which landed on the planet with a little rover to much acclaim in 1997.

''When you're launching missions at such a vast and rapid rate, there is simply statistically a greater trend that you're going to have a loss,'' said Carl Pilcher of NASA's Office of Space Exploration.

''We went into this with our eyes open, and we understood that that greater rate could mean a loss. We're going to persevere,'' he said.

The Climate Orbiter was last heard from about 2:06 a.m. PDT, five minutes after its main engine had fired to slow down the spacecraft so that it would be captured in the planet's orbit. Controllers at NASA's Jet Propulsion Laboratory cheered at the news.

As the probe flew behind Mars, controllers expected to lose its signal briefly, then regain it at 2:26 a.m., as it came back into view.

But controllers quickly learned that the probe's closest approach was about 121/2 miles under the lowest survivable altitude.

As the minutes ticked past, worry spread across their faces. One man twisted his wedding ring; another sat on the floor.

The Orbiter carried instruments designed to study the atmosphere and the fate of water that was believed to have once pooled in huge oceans on the planet. The information is key to understanding whether life ever existed or can exist there.

In 1993, the Mars Observer vanished as its fuel lines were being pressurized before the craft's descent into orbit. An investigating panel concluded that a fuel line had probably broken during the long journey through space.

The Climate Orbiter was the first of two probes arriving at the Red Planet this year in a $327.5 million exploration program.

The Orbiter's companion, the Mars Polar Lander, was launched separately and is due to arrive Dec. 3. NASA said that mission will not be compromised by the destruction of the Climate Orbiter.